Introduction to Biology and Cellular Biology

Introduction to Biology

• Biology is the scientific study of life, encompassing the structure, function, growth, origin, evolution, and distribution of living organisms.
• It's a broad field encompassing subdisciplines like botany, zoology, microbiology, and ecology.
• Biological principles are applicable in medicine, agriculture, and environmental science.
• Biology integrates knowledge from chemistry, physics, and mathematics.

Cellular Biology

• The cell is the fundamental unit of life.
• Cells are highly organized with organelles performing specific functions.
• Prokaryotic cells (bacteria and archaea) lack a nucleus and membrane-bound organelles.
• Eukaryotic cells (plants, animals, fungi, and protists) have a nucleus and complex membrane-bound organelles.
• Cell membranes regulate the passage of substances.
• Cellular processes like respiration, photosynthesis, and protein synthesis are vital for life.

Genetics

• Genetics studies heredity and variations in inherited traits.
• Genes are DNA segments that code for proteins.
• DNA is a double-stranded helix carrying genetic information.
• RNA plays a role in protein synthesis.
• Mutations change the genetic code, leading to variations.
• Mendelian genetics describes inheritance patterns based on dominance, recessiveness, and segregation.

Evolution

• Evolution is the process of species change over time.
• Natural selection is a key evolutionary mechanism where organisms better suited to their environment thrive and reproduce.
• Adaptations enhance survival and reproduction in specific environments.
• The fossil record supports the gradual evolution of life forms.
• Common ancestry connects different species through shared evolutionary history.

Ecology

• Ecology studies the interactions between organisms and their environment.
• Ecosystems consist of biotic (living) and abiotic (non-living) components.
• Food webs show energy flow and relationships in ecosystems.
• Biodiversity is the variety of life in a region or ecosystem.
• Human activities impact ecosystems, causing habitat loss and extinction.

Microbiology

• Microbiology studies microscopic organisms like bacteria, viruses, fungi, and protozoa.
• Bacteria, prokaryotic single-celled organisms, play crucial roles in ecosystems (e.g., nutrient cycling, decomposition).
• Viruses are non-cellular entities needing a host cell to replicate.
• Fungi are eukaryotic organisms involved in decomposition and nutrient cycling.
• Protozoa, single-celled eukaryotes, can be free-living or parasitic.

Plant Biology

• Plant biology studies plants, including their structure, function, reproduction, and evolution.
• Plants are producers, converting light energy to chemical energy through photosynthesis.
• Plant morphology describes plant structure.
• Plant physiology examines internal processes (e.g., water transport, nutrient absorption).
• Plant reproduction includes sexual and asexual methods.

Animal Biology

• Animal biology studies animal structure, function, development, evolution, and behavior.
• Animal diversity encompasses vertebrates (with backbones) and invertebrates (without backbones).
• Animal physiology explores internal processes and adaptations.
• Animal behavior (ethology) studies animal interactions with their environment and each other.
• Animal evolution traces the evolutionary history and relationships among animals.